Tally accounting package, version 9, is installed on several PCs, all running Windows XP, SP 2 and members of a Windows domain.
The domain control also runs the Tally license server, the Microsoft DHCP server and Microsoft DNS server. The client computers all have their primary DNS server set to the address of the domain controller.
The tally.ini file for the clients specifies the license server by its IP address.
The server can be pinged from failing clients and a telnet to port 9000 connects.
Immediately after rebooting the server the clients are able to obtain a license, but after some time (less than an hour) the error returns.
If the clients primary DNS server address is set to an external DNS server, or even to an unused IP address, then Tally successfully gets its license.